Most of the electrical rotation tools, such as electrical hand drill, are provided with a torque adjusting device to allow the user of the tools to adjust the output torque provided by the rotation tool. Indications may be provided to indicate the torque set by the adjusting device. Conventionally, the torque adjusting device is made rotatable about the axis of the rotatable output shaft of the rotation tool. However, the operation of the adjusting device in the conventional designs is non-cyclic and it is in general only allowed to move in a predetermined direction to, for example, increase the output torque by clockwise rotation of the adjusting device while counterclockwise rotation reduces the torque output. In other word, once a user wishes to increase the torque output, he or she has to rotate the adjusting device in the clockwise direction and if he or she needs to lower the torque output, then he or she has to rotate the adjusting device in the counterclockwise direction. This, to some extent, is inconvenient to the general users.
Thus it is desirable to have a torque adjusting device adapted to be incorporated in a rotation tool, the adjusting device being capable of full-turn, cyclic rotation for setting the torque output in a cyclic direction and further capable to operate in a bidirectional fashion so as to overcome the problems encountered in the conventional designs.